An ion implanter is used to generate and direct ions towards a workpiece. A desired impurity material may be ionized in an ion source, the ions may be accelerated to form an ion beam of prescribed energy, and the ion beam may be directed at a front surface of the workpiece. In one application, the workpiece may be a semiconductor wafer where the energetic ions are embedded into the crystalline lattice of the semiconductor material of the wafer. The ion beam may be distributed over the wafer area by beam movement, by wafer movement, or by a combination of beam and wafer movement.
An ion implanter may have a terminal structure. The terminal structure may sometimes be referred to in the art as a “terminal” or “high voltage terminal” and is fabricated of conductive material such as metal. The terminal structure may have varying geometries that define a terminal shape. The ion source is contained within the terminal structure. The terminal structure may be energized to a terminal voltage to increase the acceleration of the ions from the ion source. The terminal structure, as well as other components and sub-systems of the ion implanter, are disposed within a grounded enclosure. Thus, the grounded housing protects personnel from high voltage dangers when the ion implanter is running.
As the terminal structure is energized, the presence of excessive amounts of particles and/or contaminants, about the terminal structure can adversely affect operational reliability of the ion implanter. These particles can include, but not be limited to, dirt, dust, debris and other types of particles such as metallic and non-metallic particles. For instance, random failures and voltage breakdowns may occur at less than desired terminal voltage levels.
Accordingly, there is a need in the art for an ion implanter having a particle trap to overcome the above-described inadequacies and shortcomings.